1. Technical Field
The present invention relates, in general, to improvements in electrical connectors and, in particular, to improvements in ground connectors for utilization with circuit cards. Still more particularly, the present invention relates to a conductive grounding clip which may be utilized to selectively ground a particular electrically conductive terminal and a substrate ground path to a conductive cover plate of a circuit card.
2. Description of the Related Art
Small-scale planar integrated circuit cards, commonly referred to in the art as "memory cards" have become increasingly popular for use in notebook, laptop and desktop computers, as well as other consumer products. Standard specifications from the Personal Computer Memory Card International Association (PCMCIA) and the Japan Electronic Industry Development Association (JEIDA) have helped to expand this relatively new industry. Although commonly referred to as "memory cards," such devices are by no means limited to data storage applications. For example, such examples may perform various I/O functions for modem and local-area network applications.
Currently, the PCMCIA standard cards incorporate a 68-pin female connector at one end and are available in multiple formats. Type I cards have a thickness of 3.3 millimeters. Type II cards perform I/O functions as modems and local-area network applications. The side edges of Type II cards are 3.3 millimeters thick; however, the main body of the cards is 5 millimeters thick. Type III cards are not really "cards" but rather 1.8-inch hard disk drives having a 10.5-millimeter-thick housing. Again, however, these cards are equipped with outside edges of 3.3 millimeters.
Such cards typically comprise a generally rectangular frame which includes an opening in either a top surface or a bottom surface thereof or, in some constructions, in both surfaces. The opening receives a circuit board and a panel or cover, then closes the opening and then closes the circuit board within the frame. A separate frame may not be utilized in certain applications, and in such applications, the circuit board is simply sandwiched between a pair of cover panels.
The circuit board utilized in such cards typically includes a generally planar substrate with at least one electrical component mounted thereon. The electrical components may include semi-conductor devices, integrated circuits, batteries, or the like.
A problem with such cards and other similar accessories is the build-up of electrical charge within the card or the creation of excess electromagnetic emissions by such cards. Electrical charges are typically built up within such a card during handling since the card is generally a portable instrument which is often carried by a user. When a card bearing an electrical charge is inserted into an electronic apparatus or the connector thereof, the charges flow to the electronic apparatus through the connecting terminals. Thus, it is imperative that an appropriate ground be established either to prevent unwanted electrical charge from damaging the device, or to minimize the electromagnetic emissions of such cards.
Numerous examples of attempts at grounding a circuit card exist in the prior art. For example, U.S. Pat. No. 5,398,154 discloses a card-grounding apparatus which includes means for discharging any static electrical charge on the card prior to mating of the card and device context by utilizing a frame having opposite sides which are conductive by providing a grounding terminal within the device into which the card is inserted. European Patent Application 0 584 728 A2 discloses a grounded memory card which also includes conductive tabs on the card cover which is utilized to create a ground path to the circuit card.
European Patent Application 0 671 704 A1 also discloses an integrated circuit card which includes a circuit board mounted in a frame wherein ground circuits are clipped to the circuit board and utilized to create an ohmic connection with a conductive trace on the circuit board. Additionally, recently integrated circuit cards have been manufactured which include a designated conductive pad on the circuit card and means for coupling that conductive pad to the conductive cover plate utilizing a spring or similar conductive element which is physically placed between the circuit card and the cover.
While each of these systems discloses a technique for protecting an integrated circuit card from an unwanted electrical charge and minimizing the electromagnetic emissions of such cards, the complexity of manufacturing of cards including these grounding clips is substantially increased. Additionally, in cards which utilize a separate grounding clip which must be retained between the integrated circuit card and the conductive cover plate, the possibility exists that the conductive element may be lost or misplaced during vibration of the integrated circuit card.
It should therefore be evident that a need exists for an efficient technique for providing a ground connection in a circuit card.